On 2015년 08월 17일 17:17, Joonyoung Shim wrote: > On 08/17/2015 04:52 PM, Inki Dae wrote: >> On 2015년 08월 17일 14:29, Joonyoung Shim wrote: >>> On 08/16/2015 02:07 PM, Inki Dae wrote: >>>> On 2015년 07월 28일 17:53, Joonyoung Shim wrote: >>>>> The drm_gem_object_release() function already performs this cleanup, >>>>> so there is no reason to do it explicitly. >>>>> >>>>> Signed-off-by: Joonyoung Shim <jy0922.shim@xxxxxxxxxxx> >>>>> --- >>>>> drivers/gpu/drm/exynos/exynos_drm_gem.c | 3 --- >>>>> 1 file changed, 3 deletions(-) >>>>> >>>>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c >>>>> index c76aa8a..ab7d029 100644 >>>>> --- a/drivers/gpu/drm/exynos/exynos_drm_gem.c >>>>> +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c >>>>> @@ -100,8 +100,6 @@ out: >>>>> exynos_drm_fini_buf(obj->dev, buf); >>>>> exynos_gem_obj->buffer = NULL; >>>>> >>>>> - drm_gem_free_mmap_offset(obj); >>>>> - >>>>> /* release file pointer to gem object. */ >>>>> drm_gem_object_release(obj); >>>>> >>>>> @@ -600,7 +598,6 @@ int exynos_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma) >>>>> >>>>> err_close_vm: >>>>> drm_gem_vm_close(vma); >>>>> - drm_gem_free_mmap_offset(obj); >>>> >>>> Without previous patch, drm_gem_free_mmap_offset is required. I guess >>>> the reason you removed above line is that you thought >>>> drm_gem_object_release function would be called by drm_gem_vm_close >>>> function which drops a reference of the gem object. >>>> >>>> However, drm_gem_vm_close should be a pair with drm_gem_vm_open >>>> function. These will be called whenever a process opens or closes the >>>> VMA. So the reference count of the gem object had already been taken by >>>> open operation when a new reference to the VMA had been created. >>>> >>> >>> This changes is not related with drm_gem_vm_close and prior patch. Why >>> should free mmap offset when mmap operation is failed? The mmap offset >>> can be used repeatedly. >> >> Isn't vm space of vm manager still used even if any user-space process >> doesn't use the region? And if mmap is failed, then the user-space >> process will be terminated. Do you think it can be re-tried? However, >> mmap system call never return -EAGAIN. Is it reasonable to you? I cannot >> understand how the mmap offset can be re-used. So can you show me some >> example? >> > > Currently, mmap offset of exynos-drm gem is made by > DRM_IOCTL_MODE_MAP_DUMB ioctl and mmap() ioctl just uses the mmap > offset. User will use same mmap offset about same gem. It's why mmap > offset made by DRM_IOCTL_MODE_MAP_DUMB ioctl is unnecessary, it's just > enough to make mmap offset from when gem is create. You can get a > reference from drm_gem_cma_helper.c file. Hmm... It's not that the mmap offset can be re-used or not. It's that the mmap offset should be released or not when mmap failed. As your original comment, the call of drm_gem_free_mmap_offset() is unnecessary if mmap offset is created when gem creation because the mmap offset is removed by drm_gem_object_release() when gem is destroyed - gem should also be released when mmap failed. Ok, let's create mmap offset at gem creation and remove it gem releasing. Will merge these two patches. Thanks, Inki Dae > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
